Duration of depressive symptoms prior to a cancer diagnosis and post-cancer memory function and decline: A longitudinal analysis of the US Health and Retirement Study

INTRODUCTION: Depressive symptoms are associated with increased risk for cognitive decline in the general population, but less is known about how depressive symptoms might influence cognitive aging after a cancer diagnosis in mid-to-later life. We aimed to determine if the duration of depressive symptoms before a cancer diagnosis is associated with post-cancer diagnosis memory function and decline. MATERIALS AND METHODS: Data were from 425 adults aged ≥50 with an incident cancer diagnosis from 2004 to 2020 and three waves of depression data prior to their diagnosis in the US Health and Retirement Study. Depressive symptoms were measured biennially using the Center for Epidemiologic Studies Depression Scale (CESD; range 0 to 8); a score of ≥3 was considered clinically relevant depressive symptoms. Duration of pre-cancer diagnosis clinically relevant depressive symptoms was categorized as never, 1 time point, or ≥ 2 time points. Episodic memory was assessed from the time of cancer diagnosis as a composite of immediate and delayed recall scores. Multivariable adjusted linear mixed-effects models estimated the association between pre-diagnosis depression duration and post-diagnosis memory function and decline. RESULTS: The mean baseline age was 68.9 years (SD: 8.6) and 52.7% were female. In the three survey waves (~6 years) prior to diagnosis, 56.7% (241/425) had no depressive symptoms, 20.0% (85/425) had depressive symptoms at 1 time point, and 23.3% of participants (99/425) had depressive symptoms at ≥2 time points. The mean follow-up time after cancer diagnosis was 6.2 years (SD = 4.7). A longer duration of pre-diagnosis depression was associated with a faster rate of memory decline post-diagnosis (-0.12 SD units/year, 95% CI: -0.22, -0.02). DISCUSSION: Increased duration of depressive symptoms prior to cancer diagnosis is associated with faster memory decline post-cancer diagnosis and may be a salient risk factor for accelerated memory aging among older cancer survivors.